Self-lowering jack



J.- C. KOPF.

SELF LOWEB ING JACK.

. APPLICATION HLED JULY 28, 1920.

Patented. Mar. 28, 1922.

4 SHEETS-SHEET 1.

4O INVEN RNEY J. c. KOPF. SELF LQWERING JACK. APPLICATION F ILED JULY 28' 1920. 1,410,576. 7 Patented Mar. 28, 1922,

4 SHEETS-SHEET 2.

ATTORNEY 4 SHEETSSHEET 3.

Patented Mar. 28, 1922.

J. C. KO PF. SELF LOWERING lACK. APPLICATION FILED JULY 28.1 920.

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was a v -w 1 :1 i in JOHN 0. nose, or Ian-Linusa. BOROUGH, PENNSYLVANIA, essrenon TO THE num- IJZAN'UFACT'UBING COMPANY, TION OF PENNSYLVANIA.

OF PITTSBURGH, FPENNSYLVANIA, A CORPORA- SELF-LOWERING JACK.

1 ,etithhfi.

Application filed July 28,

To all whom it may concern:

Be it known that 1, JOHN C. Korr, a citizen of the United States, and resident of the borough of llellevue in the county of Allegheny and State of Pennsylvania, have invented a new and useful Self-Lowering Jack, of which the following is a specification.

The invention is an improvement in selflowering nigh-speed screw-jacks. An object is to provide a jack mechanism of this character possessing great simplicity with strength and durability, and sate andeiiicient in operation.

The jack shown herein exhibits a specifi cally different embodiment of the invention of my prior Patent No. 1,321,456, dated Nowember 11., 1919, wherein the jack is automatically locked against running down by a cushion-slippage multiple-disk device, which is compacted by the end-thrust of a quick witch worm meshed by a worm-wheel, which in turn has connection with the quickpitch lifting screw, so that the load acts through the worm upon the lock. in the particular form illustrated in that patent both sets of "lat-faced friction elements included in the device were rotatable, one set being connected with the worm and the other set beiin held and released by a manually-operated brake. In the present instanceIv-ahile one set of disks is rotatable with the worm, the second set is fixed in respect to rotation, and manually-operated means of a positive and exact nature is provided for removing and restoring the end thrust pressure between the disks, as by backing of? the worm against the action of the load, reverse operation of the control device permitting the load again to bank the disks against the fixed support of the frame. li y disposing this brake pile so that it receives the end-thrust oi the worm under load, the advantage set forth in my prior patent is realized, namely that the locking action increases with the load, so that safe holding and stopping are insured under any load, with at all times a capacity for slight slipping in bringing the load to rest; furthermore, during the lifting action, pressure on the disks is automatically removed. In the preferred embodiment of the present in- Specification of Letters Patent.

Patented Mar. 28, 1922. 1920. Serial no. 399,468.

vcntion, therefore, the collection of disks acts as a combined automatic lock for lifting and a manually-operated brake for lowering. The advantages of the invention may be secured in part, however, by specifically difirren't combinations and arrangements, and I do not necessarily limit myself to the precise embodiment illustrated in the accompanying a part hereof:

Figure 1 is a rear elevation of a ack embodying the invention;

Fig. 2 is a vertical section taken in the plane of the axes of the worm and main operating shaft;

Fig. 3 is a vertical section on the line 33 of Fig. 2, illustrating the locked condition;

' Fig. is a fragmentary view corresponding to Fig. 3, but showing the open condition at the brake lock;

Fig. 5 is a cross-section on the line 5-5 of Fig. 3;

Fig. 6 is a cross-section on the line 66 01 Fig. 3;

drawings, forming F ig. 7 is a crosssection on the line 7-7 of Fig. 3;

Fig. 8 is a perspective view of a disk of one of the sets; and

Fig. 9 is a perspective View of a disk of the other set.

The jack has a closed housing frame, comprising an expanded supporting base 1 with a hollow standard 2 rising therefrom and an annex at the back or side, near the bottom. ."L cylindrical ram 4: having a small head 5 is contained within the standard in the lowered condition, and has slidable hearing in a rigid guide portion 6 at the top. The ram is also hollow to accommodate the vertical. steep-pitch screw 7 which is sup ported by a ball-bearing 8 upon the top of the base proper. The vertically-movable ram or jacking member is held against turning by a key 9 in the upper portion of the standard cooperating with a vertical groove 10 in the ram, and at its lower end the ram has a nut 11 to cooperate with the screw.

A horizontal main operating shaft 12 is journaled in a bearing 13 in the outer wall 14 of the annex 3, and is geared to the screw by a bevel pinion 15 on its inner end meshing with a bevel gear 16 keyed to the lower portion of the screw. A worm wheel 17 is fixed by a key 18 to the operating shaft, behind the bevel pinion 15 and between the same and the inner end of the bearing 13 which projects for a substantial distance within the annex. Said worm wheel meshes with a worm 19 having shaft portions 20, 21, the axis or shaft of the worm being transversely above the main operating shaft 12. The shaft 12, the outer portion of which will be understood to be formed for operation by the usual lever and pawl rocker, may be termed the lifting shaft, and the worm, or its axis, the holding and lowering shaft. The worm and worm-wheel are of sufficiently steep pitch, so that, like the screw, they will run. down by gravity under the action of the load, the worm-wheel driving the worm. A portion of the action of the load which is transmitted to the worm produces an endthrust therein, which acts toward the left in Figs. 3 and at of the drawings. To hold and release the worm, and therefore the jacking member, means are provided which will now be described.

In the particular construction illustrated the worm 19 and parts associated upon its axis are housed in a transverse barrel-like chamber 22 merging with the top of the annex and the back of the standard. The shaft or journal portion 20 is journaled in a bearing 23 in the inner-end of this chamber, and the journal end of the other shaft portion 21 turns within a bearing in a gland which is screwed into a wide-mouthed entrance 26 in the outer projecting end of the chamber. ()n the shaft portion 21, between the worm and the inner end of the gland 25, is a collection off-lat, smooth faced friction disks 2?, 28, of which the set 27 is coupled to the worm shaft for rotation therewith, while the Set 28 is rigidly anchored against turning. Thus positioned, the pile of friction elements is adapted to be compacted by the end-thrust of the worm under load. The combined friction of the surfaces is such as to insure safe holding under any conditions, but need not be excessive, since the pressure producing locking is auton'iatically adjusted to the load. With such a device there is a desi "able momentary cushioning slippage when used as a brake to arrest the momeir tum of lowering.

The rotarydisks 27 are coupled to the shaft in respect to rotation, with capacity for slight longitudinal movement thereon, by means of longitudinal ribs or integralkeyg 29 pinched out of an intermediate portion of the shaft, and cooperating notches 30 at the sides of the central holes 31, whereby the disks are strung upon the shaft The anchored disks 28 have larger central. openings 32, permitting free rotation of the shaft therein, and are of larger outside diameter than the disks 27, so that they may have ex ternal notches 33 formed therein for engagement with integral side libs 3e formed on the frame at opposite sides of the chamber 22. The end-thrust of the worm'is preferably exerted upon the disks through a collar or spacer 35, and is solidly sustained by the inner end of the gland 25.]

In order to effect lowering, means are provided for removing or relieving the pressure between the alternating friction elements, so that those connected with the worm may turn relatively to the interjacent stationary elements. This is best and most simply accomplished by forcing the worm endwise against the action of the load. As illustrated, an axially-disposed screw 36 extends inwardly from the outer end of the bearingbushing 2d of the gland 25, the outer portion of said bushing being internally screwthreaded to engage with the threads of the screw; On the outer end of the screw is a crank 37 constituting a manual control handle for lowering and stopping of the load. By turning this handle the screw is caused to exert a. counter-thrust upon the end of the worm shaft portion 21, so as to loosen the contact or produce slight separation between the disks. For purposes of illustration the extent of this end movement of the worm and its shaft and the loosening ofthe disks for lowering has been exaggeratedin the drawings. A thrust-ball 38 is desirably interposed between the ends of the screw and shaft. Owing to the screw 16, it is possible to control the multiple-disk brake-device with ease and with great nicety. affording a sure control. which is furthersafeguarded because the flat surfaces do not seize instantaneously in case of the brake being let in suddenly;

The gland 25 and the entrance 26 which it occupies permit the introduction and assemblingof the partson the worm shaft, and constitute an adjustable abutment for the pile of disks, such adjustment being locked by means of a screw ring 39. By proper adjustment ofsuch abutment the sink-back.

due to end movement of the worm after each liftin stroke, can be reduced to a minimum: and in like manner the maximum amount of separation or loosening of the friction disks that can be produced by operation of the handle 3? can be regulated so as to permit either comparatively free or restrained lowering. V

The inclosing base-frame is preferably constructed of two sections, a base section 4:0 and a standard section 41, with'the annex 3 integral with the lowerpart of the standard section and its outer wall 14: con stituted as a removable- COVBPIPlZttG. The sections 40 and 4-1 have rircular .interfit ting alining. formations 42. 4-3 on their meet ing parts, and are united by bolts 44; and the rear opening of the annex is made circular to receive a circular alining shoulder 45 on the cover plate, which is secured by bolts 16. r

The operation of the jack will be readily understood. The ram is elevated and the load lifted by ratcheting the shaft 12 in the usual manner, so as to rotate the screw through the gears 15, 16. During the lifting movements the end-thrust pressure of the worm is removed fromrthe multiple-disk brake lock, but after each effort the load reapplies the pressure, thus locking the worm. and thereby the whole system against rotation and descent, by a clamping which is proportional to the load. In this action slippage between the disks, which would mean negative work, practically does not occur because the parts do not gather momentum. In order to lower the load. the operator moves the handle 37 in the direction to cause the screw 36 by slight end movement to ease off the lowering shaft and worm, thereby relaxing or freeing the frictional grip of the disks upon each other, and. permitting the jack to run down, the disks 27 then rotating between the stationary disks 28. 7 By manipulation of the handle so as to cause the screw to act endwise of the assemblage, the operator produces slight eX- pansion and compression of the series of plane surfaces encircling the axis of the lowering shaft. and thus controls the descent with precision. The load on the jacking member is stopped at the desired point by permitting or causing the disks to come into full contact, the stationary disks acting as a brake upon the rotating disks. It will. he understood that, while the amount of movement in respect to the disks has been magni fied in the drawings for clearness of illustration, a partial rotation of the handle is all that is required for complete control. Owing to its nature and also to the positive and exact character of its manual control,

the brake is not subject to fortuitous application, and it is simple for the operator to slow up and stop the fall quickly and gen tly; yet if he should act abruptly, the stopping will be cushioned by slipping of the disks; this property of the lowering means being of great importance in jacks of this character, whichhave heretofore been subject to breakage, with serious consequences, by the sudden stopping of heavy loads. Such slipping, of course, ceases as soon as the end-thrust due to load, and the friction, overcome the momentum tending to keep the worm in rotation.

The construction, it will be observed, is very simple and compact, as well as eflicient, the entire lowering mechanism being on a single shaft or axis.

What I claim as new is:

1. A jack having a screw adapted to be rotated by the load, and means for actuating the screw to lift the load, a worm-wheel having connection with the screw, and a worm meshing the worm-wheel and adapted to be driven thereby, in combination with a cushion-slippage locking device subject to the end-thrust of the worm, and means for effecting lowering of the load by removing and restoring the end-thrust pressure between the members of the locking device.

2. A jack having a screw adapted to be rotated by the load, and means for actuating the screw to lift the load, a worm-wheel having connection with the screw, and a worm meshing the worm-wheel and adapted to be driven thereby, in combination with lock comprising alternating fiat friction elements subject to the end-thrust of the worm, one part of the lock bein connected with the worm. and a fixed anchorage for the other part, and means for opening and closing the lock.

3. A jack having a screw adapted to be rotated by the load. and means for actuating the screw to lift the load, a worm-wheel having connection with the screw, and a worm meshing the worm-wheel and adapted to be driven thereby and having a shaft. in combination with a multiple-disk device on the worm-shaft subject to the end-thrust of the worm, one of the sets of disks of the device being engaged with the shaft, and a fixed anchorage for the other set, and a lowering control operative endwise of the assemblage.

4. A jack having a screw adapted to be rotated by the load, and means for actuating the screw to lift the load, a worm-wheel having connection with the screw, and a worm meshing the worm-wheel and adapted to be driven thereby. in combination with a multiple-disk lock adapted to be compacted by the end-thrust of the worm under load. one part of the lock being connected with the worm, and the other part being restrained against rotating therewith, and lowering means operative to back off the worm.

A jack having a screw adapted to be rotated by the load, and means for actuating tne screw to lift the load. a worm-wheel having connection with the screw, and a worm meshing the worm-wheel and adapted to be driven thereby and having a shaft, in combination with a lock comprising friction members adapted to be forced together by the end-thrust of the worm under load, one part of the lock being engaged with the worm-shaft, and the other part being restrained against rotating therewith, and a lowering screw cooperative with the shaft.

6. A jack having a screw adapted to be rotated by the load, and means for actuating the screw to lift the load, a worm-wheel having connection with the screw, and a worm meshing the worm-wheel and adapted to be driven thereby, in combination with a locking device comprising friction members subject to the end-thrust of the worm, and maneally-operated lowering means for separating said members.

7. in self-lowering jack having lifting means, locking means comprising a wormwheel and an endwise-movable worm adapted to be driven by the worm-wheel, a friction lock subject to the end-thriiist of the worm, and manual means for moving the worm endwise against the action of the load.

8. A self-lowering jack having lifting means, and a casing, locking means comprising a worm-wheel and an endwise movable worm and a worm-shaft adapted to be driven by the worn'i-wheel, a lock comprising alternating friction elements adapted to be compacted by the end-thrust of the worm under load, one part of the lock being connected with the worm means com prising lugs on the interior of the casing for anchoring the other part against rotation, and manual means controlling the lock.

9. In a self-lowering jack, the combination of a casing containing a. chamber having side lugs in its interior and a journal bearing" at one end and an entrance at the opposite end, a. gland in said entrance containing a journal bearing, a worm havinga shaft journaled in said bearings, a collection of friction diskson the shaft between the worm and the end support afforded by said gland, the disks being engaged alternately with the shaft and with said casing lugs, and a screw in the gland cooperative with V the end of the shaft.

it). A jack, having a jacking member, a

lifting screw adapted to be rotated by the load, and mechanism connected with the screw adapted to permit the jack to run down by gravity and including a terminal shaft, of a device for holding, lowering and stopping the load on the jacking member comprising a collection of fiat friction elements, adapted to be compacted and loosened, encircling said shaft and constituting a set engaged with said shaft to rotate therewith, and a stationary set in alternate engagement with the first, and a fixed support whereon toe second set is held against rotation. v V

11. In a self-lowering jack, the combination of a quick-pitch lifting screw, a WOIHIP wheel having connection therewith, a worm meshing the worm-wheel and of a pitch to be driven thereby, a worm-shaft, and a multiple-disk brake on said shaft, comprising rotary disks engaged with the shaft and stationary disks alternating with the rotary disks, a fixed anchorage for the stationary disks, and manuallyoperatecl means for causing the separation and compression of the disks. o

12. In a self-lowering jack, the combination with a vertically-movable acking member and lifting means, of a lowering shaft having a worm in driven relation to the load on the jacking member, a multiple disk device comprising alternating station ary and rotatable members subject to the end-thrust of the worm under load, an adjustable abutment, and means for removing and restoring'the end-thrust pressure on the members.

13. In a selflowering jack, the combina tion of a liftingscrew adapted to be rotated by the load, a lifting shaft geared to'the screw and bearing a worm-wheel, a lowering worm meshing said worm-wheel and and manually-operated means adapted to cause separatlon and compression of the members.

JOHN C. KQPF. 

